Texas Republican Gov. Rick Perry on Sunday again floated a theory that President Barack Obama and the federal government might be "in on" coordinating a surge of immigrants illegally crossing the U.S.-Mexico border, prompting a grilling from ABC's Martha Raddatz.

Perry first put out his suggestion last week during an appearance on Fox News, when he said the Obama administration "might be in on this somehow." On ABC's "This Week," Raddatz asked Perry if he "really believes" there is "some sort of conspiracy to get people in the United States."

Perry, who is weighing a second presidential run in 2016, said he had sent a letter to the Obama administration in May 2012 warning of the surge in unaccompanied minors crossing the border. The fact he had yet to receive a response, he said, proved the administration was either inept or doesn't care about the crisis.

"When I have written a letter that is dated May of 2012, and I have yet to have a response from this administration, I will tell you they either are inept or don’t care, and that is my position," Perry said.

"We have been bringing to the attention of President Obama and his administration since 2010. He received a letter from me on the tarmac. I have to believe that when you do not respond in any way, that you are either inept, or you have some ulterior motive of which you are functioning from."

Obama administration officials said last month that, as of June 15, 52,000 unaccompanied children from Central America have been apprehended at the U.S.-Mexico border. In addition, border officials have taken into custody 39,000 more adults with children as of May 31.

Hundreds are coming over the border every day, mostly making their way from violence-stricken areas in Honduras, Guatemala, and El Salvador. The causes for the influx are many, but a large portion are children fleeing increased drug and gang violence.

Perry said the "real issue" has been Obama's policies on immigration, which he said have been too lenient toward illegal immigration and have given people the false impression they can migrate to the U.S. without consequence.

"The president has sent powerful messages time after time — by his policies, by nuances that it is OK to come to the United States and you can come across and you’ll be accepted in open arms. That is the real issue," Perry said.

Raddatz continued to press Perry, asking him whether a 2008 law signed by then-President George W. Bush is at all to blame for the current crisis. The law, opponents argue, has made it nearly impossible to fast-track deportations, leading to a backlog in federal courts.

When Raddatz asked Perry if that law should be changed, he demurred.

"The rule of law is that the Constitution requires the United States to secure the border," he said. "And we're not doing that. We haven't done it for years. And we are paying a huge price."